NH 270 sheer bolt

Two questions...first, is that sheer bolt supposed to be a grade 2, 5/16-18 bolt about 2 or 2.5" long? If not, what is it suppsoed to be?

Second, and more crucial - the cause of the sheering. It seems that it will sheer when the plunger is on its compression stroke. Timing doesn't seem to be a problem, as the knotter isn't doing anything, and the fingers are out of the way. When the the bolt sheered, there was a big wad of hay stuck between the knives on the bale chamber and plunger. I sharpened both knives, hoping that the bolt was sheering because the plunger simply was trying to push too much hay through the (dull) knives. Would dull knives cause this problem? Should we look for anything else? We are almost done with this cutting, so I'm planning to spend some time cleaning it up and doing some maintenance on it before next cutting (we got it 3 weeks ago)

Thanks in advance.

If you have already checked the timing, another thing you may want to check is the knotter brake. I bought my 270 from a fellow who was plagued with breaking shearbolts. (I cleaned out at least 30 broken bolts from the toolbox.)

What I found was the knotters had been overgreased, and the knotter brake was coated as well. This allowed the knotters to rotate slightly (when the knotters were at rest) and engage the needle safety latch, which stops the plunger and breaks the shearbolt. Cleaning the knotters and 2 new brake linings cured the problem.

With regard to the plunger knives, they need to be sharp if you intend to make nice square bales. Be sure to check the 10 ball bearings on the plunger, as they need to be in good condition in order to get the desired knife clearance (no more than 1/32") when reinstalling and reshimming the knives.

As far as replacement shear bolts, I get the OEM bolts from my CNH dealer. They were not expensive. Be sure to use a locknut and tighten it securely.

Good Luck!

Scott Goff

Is there a loud bang & jolt when the bolt sheers? There is a catch arm on the left side that protects your needles. The little but heavy arm will catch the plunger & break the shear pin. Sometimes a loose brake or mis adjustment of the linkage from the arm back to the yoke will make that arm catch the plunger.

Otherwise, feeding too much wet hay into my 270 will make the shear pin break. It does this frequently if the shear pin loosens (hence the compression nut...) or if the hay is really roped & clumpy & a bit too wet. A sharper knife certainly helps.

--->Paul

Not sure about the 270, but I have a 320 with the same shear bolt. If the bolt shears as soon as you start the PTO, you can try turning the flywheel by hand backwards through almost an entire stroke. This allows the the plunger to build speed through the return stroke and a complete compression stroke be fore hitting the hay. I don't recall the specifics on what kind of bolt it is, I just buy the shear bolt from a dealer. Dull knives will contribute to the problem but I don't think it would cause it continuously unless the hay was extremely thick.

Just some thoughts,
Clay

It has always been this way I'm told so I look at the knives, big chunks out of them and duller than a splitting maul, no wonder it delivers so many siamese bales!

The new to us JD 336 will bale at idle with it's sharp knifes.
Ken